Indirect Selection for Seed Yield in Sacha-Inchi (Plukenetia volubilis) in Brazil

Breeding programs for improvement of sacha-inchi, Plukenetia volubilis L., generally aim to select individuals with greater seed yield since there is a strong correlation between seed yield and oil production. However, the manual removal of seed husks for evaluating this trait is laborious and costly, thereby discouraging breeding efforts. Accordingly, the objective of the present study was to estimate gains from indirect selection of seed production in sacha-inchi progenies, focusing on maximizing efficiency in improvement programs. Genetic parameters along with direct and indirect selection gains were estimated for seed yield traits in 12 open-pollinated progenies. Strong genetic correlations were observed between total number of fruits (TNF), total weight of fruits (TWF), and total weight of seeds (TWS) per plant (r > 0.96). Notably, all three traits demonstrated high heritability (h2 > 0.81). Therefore, plants with high TNF and TWF (Cuzco, Dos de Mayo, Shanao, Aucaloma, and AM-7) can be used to indirectly select the genetic traits of higher seed yields (GS% = 23%). Genetic gain for dry seed production with a selection index of 42% was estimated at 23%, which corresponds to 118 kg·ha−1. Future sacha-inchi improvement programs can select progenies with high TNF and TWF to facilitate the selection of progenies with high TWS.